1. Field of the Invention
The invention relates to a 3/2-way valve for controlling the injection of fuel in a common rail injection system of an internal combustion engine, having a control member guided in a housing, wherein the control member in a first switching position opens a hydraulic communication between an injector and a fuel return, and in a second switching position the control member opens a hydraulic communication between the injector and a common rail.
2. Description of the Prior Art
One 3/2-way valve of the above type is known for instance from German Patent Disclosure DE 197 24 637 A1. In common rail injection systems, a high-pressure fuel pump pumps the fuel into the central high-pressure reservoir, which is called a common rail. From the rail, high-pressure lines lead to the individual injectors, which are assigned one to each of the engine cylinders. The injectors are triggered individually by the engine electronics. When the control valve opens, fuel subjected to high pressure moves past the nozzle needle, which is lifted counter to the prestressing force of a nozzle spring, to reach the combustion chamber.
The object of the invention is to improve the function and quality of the injection. Moreover, the control valve of the invention should be simple in construction and it should be possible to produce it economically.
In a 3/2-way valve for controlling the injection of fuel in a common rail injection system of an internal combustion engine, having a control member guided in a housing, wherein the control member in a first switching position opens a hydraulic communication between an injector and a fuel return, and in a second switching position the control member opens a hydraulic communication between the injector and a common rail, this object is attained in that the control member includes a first control piston and a second control piston; that between the housing and the first control piston a first valve seat is embodied; and that between the housing and the second control piston, a second valve seat is embodied.